The Internet, as well as other networks, has become more complicated with additional bandwidth requirements, a larger number users, and increasingly elaborate uses. In order to handle these increased demands, new protocols and network data types have been developed. Network Processors (NPs), which are well known to those of ordinary skill in the art, are used to perform various tasks such as processing network packets, network data streams, and network objects to accomplish specific tasks.
The functions that the NP performs can be generally categorized into physical-layer functions, switching and fabric-control functions, packet-processing functions, and system control functions. In some instances, the packet-processing functions can be further subdivided into network-layer packet processing and higher-layer packet processing.
The physical-layer functions handle the actual signaling over the network media connections, such as an Ethernet port, an optical fiber connection, or a coaxial T3 connection. The NP converts the data packets into signals that are transmitted over the physical media. These often work according to a media access control (MAC) and physical layer protocols such as Ethernet, Synchronous Optical Network (SONET), Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA), and the like.
The switching and fabric-control functions performed by the NP direct data from the ingress port of the NP to an appropriate egress port of the NP. Further functions include performing operations, such as queuing the data in appropriate order or priority at these ports.
The packet-processing functions performed by the NP handle the processing of various network protocols. Thus, a packet containing instructions on allocating a stream for continuous guaranteed delivery is handled at this level.
System-control or host-processing functions performed by the NP include the management of other components of the hardware unit, such as power management, device control, console port management, and the like.
NP processing typically includes other functions as well. A typical router application involves receiving packets, performing route table look-ups, packet classification, packet metering, congestion avoidance, packet transmit scheduling and packet transmittal. NPs should provide sufficient processing power in order to run network applications efficiently and cost-effectively.